Read USB unique identifier?

I have a project where I read waypoints into a FM database from a .gpx file, previously downloaded onto the local drive from a Garmin GPS, via USB. This is triggered by a script, and requires an xslt file to enable FM to read from the .gpx file. We use many GPS's and during the import process each GPS must be identified manually by the database operator - an error in this phase means that the waypoints cannot be correctly associated with related records in another database.

My question is this: Do USB devices have a unique identifier? and if so is there any way that this can be read by FM (via script / plugin) so that, during the download/import process, I can automatically identify what data was imported from which device. I am looking for a soultion that will work on Windows OS, and cross platform functionality would be a bonus.